Immense results, moreover, followed upon the unrelenting war which Juvenal waged upon all profane songs. Like St Philip, he strove to use music for its highest end, and it was through his persevering exertions that the idea of the Saint in regard of the spiritual and sanctifying power of music was so deeply implanted in the Oratory of Naples.*
He endeavoured to procure copies of all the songs that went about the town, and set other and devout words to them, composed either by himself or some of the Oratorian fathers; and with the object of banishing all profane or immodest songs, not only from Naples, but also from the whole of Italy, he published a book of hymns set to music, called "the Temple of Harmony," and dedicated to the Blessed Virgin. On the frontispiece was the Madonna and Juvenal kneeling before her, offering her some books with the words: "Dignare me laudare te, Virgo sacrata."
Life of Blessed John Juvenal Ancina: companion of St. Philip Neri, Bishop of Saluzzo (1891)
One was that of the renowned singer, Donna Giovanna Sancia, whose voice and singing were so perfect that she commonly went by the name of "The Siren." She was the occasion of the greatest danger to the youth of the city, who could not withstand her charms; but when Juvenal took occasion to speak to her of Heaven and the beauty of virtue, the light of the Holy Ghost penetrated her heart, she beheld the miserable state of her soul, and, to the great edification of the city, she changed her ways, made a sincere confession of her whole life to Juvenal, and, in order to render her purpose of amendment ininviolable, she pronounced a solemn vow never again to sing a profane song, but only moral or sacred ones.
This vow, which was written for her by Blessed Juvenal, ran as follows:—
"I, Giovannella Sancia, declare and promise to God that never again will I utter or sing any Spanish or Italian vain, impure, or profane song; but only psalms, hymns, motets, or devout spiritual canticles, to praise the Supreme Majesty of God our Lord, the Glorious Virgin, and the angels and saints of the Heavenly Paradise. Amen, so be it.
"Signed by me, the day of the Glorious Apostle and Evangelist, St John, my holy Patron, in Naples, the sixth of May 1596, Giovannella Sancia, after having received Communion at the sacred altar of St Januarius in. the Cathedral, at the hands of the Rev. Father Juvenal Ancina, my spiritual father."
She pronounced this vow in the presence of her father and mother, after which the Blessed Juvenal closed her mouth, saying: "On the part of God and of St Januarius, I close this mouth, that never again thou mayest open it to sing profane songs or words." (page 96)